valence tautomerization
The term describes simple reversible and generally rapid isomerizations or degenerate rearrangements involving the formation and rupture of single and/or double bonds, without migration of atoms or groups; e.g.
See also: fluxional, tautomerism
PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1175 (